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The Environment Today
Published in Anco S. Blazev, Power Generation and the Environment, 2021
Drilling fluids are used to lubricate, cool and regulate drill pressure. They, however, contain petroleum products and heavy metals, which are toxic to marine life. The impacts of drilling fluids differ significantly, because they are made up of different types and concentrations of chemicals, and are applied in many different ways. Documented impacts from drilling fluids include effects on the health and reproduction of marine life, reducing the populations of bottom-dwelling creatures and biomagnifying toxic substances in the food chain. Using drilling fluids that have low aquatic toxicity and high biodegradability is one solution.
Techniques for Subsurface Characterization
Published in Stephen M. Testa, Geological Aspects of Hazardous Waste Management, 2020
Rotary drilling techniques include direct mud rotary, air rotary, air rotary with a casing driver, and dual-wall reverse circulation. With direct mud rotary, drilling fluid is pumped down through the bit at the end of the drill rods, then is circulated up the annular space back to the surface. The fluid at the surface is routed via a pipe or ditch to a sedimentation tank or pit, then to a suction pit where the fluid is recirculated back through the drill rods. Air rotary drilling is similar to that of direct mud rotary, except that air is used as a circulation medium instead of water. Although the air helps cool the bit, small quantities of water or foaming surfactants are used to facilitate sampling. In unconsolidated deposits, direct mud or air rotary can be used, providing that a casing is driven as the drill bit is advanced. In dual-wall reverse circulation, the circulating medium (mud or air) is pumped downward between the outer casing and inner drill pipe, out through the drill bit, then up the inside of the drill pipe.
Esters
Published in Leslie R. Rudnick, Synthetics, Mineral Oils, and Bio-Based Lubricants, 2020
Ester-based organic compounds are one type of SBF added to drilling muds used during offshore oil-drilling operations. Since 1990, the oil and gas extraction industry developed SBFs with synthetic and nonsynthetic oil-like materials as the basefluid to provide the drilling performance characteristics of traditional oil-based fluids (OBFs) based on diesel and mineral oil. Drilling fluids are needed to cool and lubricate the drill bit and to help bring rock cuttings to the surface. Ester-based drilling fluids have the following advantages over OBFs:Faster and deeper drillingGreater worker safety through lower toxicityElimination of polynuclear aromatic hydrocarbons (PAHs)Excellent biodegradability and lower bioaccumulation potentialPotentially less drilling waste volumeReduced drilling costs
Effect of excess viscosifier and fluid loss control additive on the rheological characteristics of water-based drilling fluid
Published in Petroleum Science and Technology, 2023
Mike Uche Ajieh, Nosakhare Andrew Amenaghawon, Kesiena Owebor, Oghenero Henry Orugba, Esua Bassey Bassey
A typical composition of water-based drilling fluids includes clay, biopolymers, weight material, starch, potassium chloride, potassium hydroxide, and biocide (Hamed and Belhadri 2009). Water-soluble polymers are used to improve drilling operations so that oil and gas wells can be drilled in less time and completed with minimized formation damage (Ouaer and Gareche 2018). It has been demonstrated that adding nanoparticles as additives can significantly improve the rheological and heat transfer properties and reduce the filtration loss and friction coefficient of drilling fluids (Rafati et al. 2018). Furthermore, several studies have demonstrated that certain substances can be added to WBDF to promote its lubricity and rheological properties and effectively perform its drilling task (Maiti, Bhaumik, and Mandal 2021). The pH of the fluid is controlled by the addition of NaOH (or KOH) and the appropriate silicate solution. Silicate anions and colloidal silica gel combine to stabilize the wellbore by sealing microfractures, forming a silica layer on shales. WBDFs can also be saturated with lime and Ca(OH)2 and have excess, undissolved lime solids maintained in the reserve (Al-Hameedi et al. 2019).
Water-based drilling fluid for ultra-long horizontal intervals in Changqing oil and gas field
Published in Petroleum Science and Technology, 2023
Jianqing Zhang, Zubiao Hu, Qin Zhang, Qingchen Wang, Huafeng Ni, Weiliang Wang, Luke Li, Chengfu Han
Drilling fluids are normally called the blood of drilling because they are responsible for well control, wellbore stability, borehole cleaning, drilling tools lubrication and cooling, and so on. Drilling fluids are composed of dispersion medium, clay and various treatment agents. According to the type of dispersion medium, drilling fluids are classified into several categories, for example, water-based drilling fluids (WDFs), oil-based drilling fluids (ODFs) and synthetic drilling fluids (SDFs) (Beg et al. 2020). The advantages of WDFs over ODFs and SDFs are widely used due to low cost, eco-friendliness, rapid cooling, and superior cutting removal ability. However, the application of WDFs is limited by high filtration loss, poor temperature resistance and lubricity. The disadvantage of WDFs will be amplified especially for the ultra-long horizontal interval. Therefore, a large number of treatment agents with excellent performances was studied and laid a foundation for the smooth construction of ultra-long horizontal interval.
Sulfonated sodium tannin and AM/AMPS copolymer complex as an anti-temperature viscosity reducer for water-based drilling fluid
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2022
Shaocong Pang, Heming Zhu, Jingyuan Ma, Luo Zhao, Chaolan Yang, Yuxiu An
With the depletion of conventional resources and the development of drilling technology, it is particularly important to drill deeper wells to obtain oil and gas resources (Abdo and Haneef 2013; An et al. 2016). As an indispensable part of drilling engineering, the drilling fluids with suitable rheological properties are necessary (Zhao et al. 2022). Affected by the high temperature, the rheology of drilling fluid is seriously deteriorated (Mao et al. 2020). The function of drilling fluids is to cool and lubricate the drill bit, carry drill cuttings, and maintain the stability of the wellbore. However, the high temperature caused the bentonite to aggregate or flocculate in deep well drilling process (Huang et al. 2015; Perween et al. 2018). In addition, the adsorption to clay was weakened due to the decomposition of major groups on the polymer chain at high temperature. (Oseh et al. 2020). Therefore, the rheology of the drilling fluid deteriorated, causing the bit balling, increase of pump pressure, and decline in drilling speed (Barry et al. 2015). Therefore, it is still a worldwide problem to control the rheology of drilling fluid within a reasonable range at high temperatures (Mohamad Ibrahim, Chuah, and Y 2012; Wang et al. 2012). In terms of reducing the viscosity of water-based drilling fluid (WBDF), the use of viscosity reducers has significant advantages in the case where bentonite and treatment agent content cannot be reduced.